The invention relates generally to valves for controlling the flow of a fluid between a first environment and a second environment, and more particularly to reducing noise generated by the fluid flowing through such a valve.
Gated valves are often used to control the flow of a fluid from one environment to another. For example, gated valves may control the flow of a fluid, such as air, from one portion of an enclosure, such as a pipe, to another portion of the enclosure, or from an inside or outside area of an enclosure, such as a mobile platform, to the respective outside or inside area of the enclosure. Typically, as the rate of flow through the valve increases, the amount of audible noise, produced by the fluid passing through the valve and over the valve gate(s), increases. For example, if a valve is controlling the flow of air, the faster the air flows through the valve and over the valve gate(s), the greater the likelihood there is of audible tones (i.e. noise) being generated by coherent vortex shedding as the air separates from the gate(s) surface. Vortex shedding occurs when a fluid passing over a surface separates from the surface due to some incongruity, e.g. a bump or protrusion on the surface. As the fluid separates from the surface the fluid begins to tumble. If this tumbling occurs at a constant rate, i.e. frequency, coherent vortex shedding occurs and tones are produced.
A more specific example would be the use of gated valves in mobile platforms. Mobile platforms, such as aircraft, buses, ships or trains, often control such things as passenger compartment air pressure, air condition/quality, and air circulation by controlling the flow of air from inside the passenger compartment to the environment outside the passenger compartment utilizing a gated valve. At various flow rates, the air passing through the valve and over the gate(s) will generate tones caused by the air passing through the valve opening and over or across the surfaces of the gate.
The noise generated by a fluid as the fluid passes through a gated valve can be nuisance to people within hearing distance and become very irritating over extended periods of time.
In one preferred embodiment, a valve for controlling a flow of a fluid between a first environment to a second environment is provided. The valve includes a frame that fits within an aperture in a divider separating the first environment from the second environment. Additionally, the valve includes at least one gate mounted and movable within the frame to control a flow of the fluid between the first environment and the second environment through the aperture. The gate includes a surface, wherein at least one portion of the surface includes a rough texture. The rough texture reduces coherent vortex shedding of the fluid as the fluid passes over the gate surface.
In another preferred embodiment, a method for controlling the flow of a fluid between a first environment to a second environment is provided. The method includes providing a valve installed in a divider separating the first environment and the second environment. The valve includes at least one gate that controls the flow of the fluid between the first and second environments. The gate includes a surface, wherein at least one portion of the surface includes a rough texture for reducing coherent vortex shedding of the fluid.
In yet another preferred embodiment, a mobile platform is provided wherein the mobile platform includes a body having an outer shell with an aperture therethrough. A valve is adapted to fit within the aperture for controlling the flow of air between an environment inside the mobile platform and an environment outside of the mobile platform. The valve includes at least one gate having a surface with at least one portion including a rough texture. The rough texture reduces coherent vortex shedding of the air as the air passes through the valve.